Bartonella Species - Bartonellosis

Bartonella spp cause several different diseases, including cat-scratch disease (CSD). Serology can confirm the diagnosis; culture is generally not recommended because of low sensitivity. PCR testing of blood, tissue, or CSF may also be helpful.

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • High level of suspicion based on symptoms and exposure risk

Laboratory Testing

  • CDC Bartonella diagnosis and treatment information for healthcare providers (2015)
  • Bartonella henselae
    • Nonspecific testing
      • CBC – mildly elevated white blood cell count and elevated or diminished platelets
    • Acute and convalescent serum specimens for antibody testing
      • 70-90% positive in immunocompetent patients
      • Best evidence of infection is significant change on 2 appropriately timed specimens where both tests are performed in same laboratory at same time
      • Confirmation requires a 4-fold change in titers between acute and convalescent specimens
      • Low-positive IgG – suggests past exposure or infection
      • High-positive IgG – may indicate current or recent infection (not conclusive)
    • Polymerase chain reaction (PCR) from whole blood, tissue, or cerebrospinal fluid (CSF)
      • Rapid test
      • Relatively sensitive, very specific
    • Culture of involved nodes
      • Difficult
      • Long incubation periods with poor yield
      • Not recommended – sensitivity very low
  • Bartonella quintana
    • Trench fever – may require culture, PCR, or serology
    • Endocarditis – blood cultures may be negative


  • Warthin-Starry silver stain
    • B. henselae – pathologic examination of involved nodes
    • B. quintana – diagnosis of bacillary angiomatosis based on histopathologic findings of angiomas associated with tiny clumps of bacilli

Differential Diagnosis


  • B. henselae
    • Incidence – 22,000 infections annually in the U.S. (~9/100,000)
    • Age – children <1 year have the greatest rate of infection
    • Occurrence – most common in warm, humid climates during autumn and winter months
    • Transmission – usually by cats to humans (fleas mainly transmit the disease directly through a cat scratch; flea-borne transmission to humans may also occur)
      • Most affected patients do not recall being scratched by a cat
  • B. quintana
    • Incidence – generally low; however, increasing prevalence in homeless populations in U.S. and Europe
    • Transmission – body louse (Pediculus humanus corporis)


  • Genus Bartonella contains aerobic, fastidious, gram-negative bacillus
  • Associated with four primary clinical syndromes
    • CSD – B. henselae, B. clarridgeiae
    • Bacillary angiomatosis – B. quintana, B. henselae
    • Bacillary peliosis hepatitis – B. henselae
    • Relapsing fever with bacteremia (trench fever) – B. quintana

Risk Factors

  • B. henselae
    • Cats with fleas – ~60% of strays and 40% of domestic cats are bacteremic for B. henselae
    • Rough play with cats – especially kittens
    • Unwashed bites and scratches from cats or allowing cats to lick open wounds
  • B. quintana
    • Immunocompromised persons – especially those with HIV
    • Homelessness
    • Alcoholism

Clinical Presentation

  • B. henselae
    • Immunocompetent host
      • Common presentations – CSD
        • Localized papule progressing to a pustule develops 3-5 days after cat scratch
          • Initial lesion heals uneventfully
        • Tender, unilateral regional lymphadenopathy develops 1-2 weeks later – 90% of cases
          • Generally persists for 2 weeks to 3 months before resolving spontaneously
          • Cervical and axillary – most common
          • Secondary bacterial superinfection of involved nodes – ~10% of cases
      • Other manifestations
        • Neurologic – encephalopathy, transverse myelitis, radiculitis, cerebellar ataxia
        • Hepatitis
        • Osteomyelitis
        • Disseminated infection (endocarditis) – associated with mortality
        • May also present as granulomatous disease
        • Ophthalmic
          • Conjunctival inoculation may cause Parinaud oculoglandular syndrome with conjunctivitis and periauricular lymphadenopathy
          • ​Neuroretinitis
    • Immunocompromised host
      • Bacillary angiomatosis
        • Nontender, firm, red-purple colored skin lesions
          • Dissemination to organs – pseudoneoplastic vasculitis proliferation
          • Potentially fatal if not treated
      • Bacillary peliosis
        • Vasoproliferation within the liver and spleen
          • Blood-filled cysts with possible organisms in the cysts
  • B. quintana
    • Trench fever
      • Sudden onset headache, meningitis, and relapsing fever
      • Relapsing fever with bacteremia
        • Relapses common when short-course antibiotics are used
      • May cause endocarditis
      • No fatalities reported
    • Bacillary angiomatosis
      • Most common in immunocompromised patients (eg, HIV)
      • Many organs may be affected –  bone marrow, lymph nodes, liver, spleen
      • Hallmark symptoms – vascular nodules, papules, or tumors with proliferation of new blood vessels (angiogenesis)
      • Lesions, termed epithelioid angiomatosis, resemble Kaposi sarcoma
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Bartonella henselae & B. quintana Antibodies, IgG & IgM 2002280
Method: Semi-Quantitative Indirect Fluorescent Antibody


If test results are equivocal, repeat testing in 10-14 days

Bartonella Species by PCR 0093057
Method: Qualitative Polymerase Chain Reaction

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification


Limited to the University of Utah Health Sciences Center only

General References

Badiaga S, Brouqui P. Human louse-transmitted infectious diseases. Clin Microbiol Infect. 2012; 18(4): 332-7. PubMed

Bartonella Infection (Cat Scratch Disease, Trench Fever, and Carrión’s Disease). Centers for Disease Control and Prevention. Atlanta, GA [Last updated: Mar 2016; Accessed: June 2017]

Bitam I, Dittmar K, Parola P, Whiting MF, Raoult D. Fleas and flea-borne diseases. Int J Infect Dis. 2010; 14(8): e667-76. PubMed

Florin TA, Zaoutis TE, Zaoutis LB. Beyond cat scratch disease: widening spectrum of Bartonella henselae infection. Pediatrics. 2008; 121(5): e1413-25. PubMed

Kaiser PO, Riess T, O'Rourke F, Linke D, Kempf VA. Bartonella spp.: throwing light on uncommon human infections. Int J Med Microbiol. 2011; 301(1): 7-15. PubMed

McElroy KM, Blagburn BL, Breitschwerdt EB, Mead PS, McQuiston JH. Flea-associated zoonotic diseases of cats in the USA: bartonellosis, flea-borne rickettsioses, and plague. Trends Parasitol. 2010; 26(4): 197-204. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

Litwin CM, Johnson JM. Identification, cloning, and expression of the CAMP-like factor autotransporter gene (cfa) of Bartonella henselae. Infect Immun. 2005; 73(7): 4205-13. PubMed

Litwin CM, Rawlins ML, Swenson EM. Characterization of an immunogenic outer membrane autotransporter protein, Arp, of Bartonella henselae. Infect Immun. 2007; 75(11): 5255-63. PubMed

Medical Reviewers

Last Update: November 2017